According to a report today, the wide variations in how much NHS trusts spend on diseases such as cancer and heart disease have remained practically unchanged for three years.

Even after the different health needs of people are taken into account there remains a huge difference in how much primary care trusts (PCTs) spend on certain illnesses. Some of this could be down to decisions by individual doctors about who to treat while some hospitals may not be as efficient as others.

The Yorkshire Post last month revealed that North Yorkshire and York PCT had refused the highest percentage of applications for drug treatment for some kinds of cancer in the region. Of 147 requests, 51 – 35 per cent – were rejected.

Professor John Appleby, chief economist at the King's Fund, who compiled today's report, said more research was needed but the study did raise questions about the "consistency of the decisions PCTs make about how much they spend on different diseases". He added: "This latest analysis reveals that the widespread variations in PCT spending on different diseases have remained relatively unchanged over the past three years.

"Even when local need and other legitimate reasons for variations in spending are taken into account PCTs continue to spend varying amounts on cancer, coronary heart disease, mental health and a range of other diseases. Some of the variations we have highlighted will not solely be as a result of deliberate choices by PCTs.

"Other factors, such as variations in decisions by clinicians about who and when to treat, and what treatment to provide, and differences in the efficiency of hospitals, will also contribute to these variations."

Prof Appleby's study, into spending in 2006-7, took account of the different health needs of populations. For example, people in some parts of the country have far more need for mental health services than in other parts.

But even when this was acknowledged wide variations in spending remained, the report found. Islington PCT in north London spent £332 per head of population on mental health but the figure was only £114 in the East Riding of Yorkshire PCT, a 2.9-fold gap.

The proportion spent on mental health ranged from 8.7 per cent to 25 per cent of PCTs' budgets, the study found.

The data showed the Government's three clinical priorities of mental health, coronary heart disease and cancer had continued to consume the largest shares of PCT spending – 12 per cent, nine per cent and just over six per cent respectively. PCTs are in charge of spending about 75 per cent of the NHS budget in England each year. In 2006-7 it was almost £69bn.

The King's Fund's chief executive, Niall Dickson, said: "This report raises questions rather than providing answers.

"It does not mean that any one PCT's spending is necessarily wrong but it does suggest that as well as unexplained variations in clinical practice there are unexplained spending variations. Some of these are almost certainly not justified.

"We need better information about what PCTs spend their money on and what gains in health they achieve... Fortunately, over the next few years we should achieve that."

Liberal Democrat health spokesman Norman Lamb said: "This analysis points to an unacceptable postcode lottery of care, with PCTs totally unaccountable to the communities they serve for these funding decisions... This report begs urgent questions as to what extent these extraordinary variations in spending are affecting patient care and leading to higher death rates. The Government must investigate whether the funding allocations are fair."